Looker is intended to connect to a single database per connection. Depending on your use case, you could create connections to multiple databases and merge the results on a Looker dashboard using the merged results functionality described here. There...

Hi Satish - there are no certifications available at the moment since the original Looker certifications were retired, but it's possible that something will be created in future - it is on the radar, but nothing is confirmed for now.

This is almost certainly an issue with the software on the TV, unfortunately.

Sending to an S3 bucket should work fine - why not test it with some data to a bucket you control? That will show up if your deployment has a set up that is blocking that approach.

Are pull requests set up on your dev instance? If not, your code will simply be deployed to production when you deploy, as you see here.